基于多层次修正的纤维增强复合薄壳动刚度预测

Prediction of the dynamic stiffnesses of fiber-reinforced composite thin shells based on the multilevel correction technique

采用多层次修正技术对纤维增强复合薄壳的动刚度进行分析与预测。用正弦半波信号来近似模拟脉冲激励信号,并基于Love壳体理论、能量法、哈密顿原理等方法,实现了该类型复合薄壳的动刚度求解。利用多层次修正技术和测试获得的试验数据,对理论模型中复合薄壳的长度、半径、厚度、弹性模量、泊松比及模态阻尼比等参数进行修正,进而获得了较为精准的理论模型。以T300碳纤维/树脂基复合薄壳为例,搭建了振动测试系统,通过力锤施加脉冲信号,并采用激光速度传感器测试了3个响应测点的动刚度,并与相应的预测结果进行了比较。结果表明,动刚度理论预测的误差最大不超过12.2%,处于误差允许的范围内,进而验证了所提出的动刚度预测方法的正确性。

The dynamic stiffnesses of fiber reinforced composite shells were analyzed and predicted based on the multi-level correction method.Firstly,a sinusoidal half-wave signal was used to approximate the impulse excitation signal,and the dynamic stiffnesses of the composite shell were studied based on the Love shell theory,energy method and Hamiltonian principle.Next,in order to obtain a more accurate dynamic stiffness model of the composite thin shells,the multi-level correction technique and the experimental data were employed to correct the length,radius,thickness,elastic modulus,Poisson's ratio and modal damping ratio.Finally,a T300 fiber/epoxy composite thin shell was taken as a study object and a corresponding vibration test system was set up.The pulse signal was applied by a hammer and the dynamic stiffnesses at three response points were tested by the laser speed sensor.The experimental results were compared with the calculated results.It is found that the predicted errors of the dynamic stiffnesses at the above points are less than 12.2%,which are within an acceptable range.Thus,the correctness of the proposed prediction method for dynamic stiffnesses was verified.